When trying to find the acidity of a solution of magnesium hydroxide in hydrochloric acid, we obtain

Question:

When trying to find the acidity of a solution of magnesium hydroxide in hydrochloric acid, we obtain the following equation
A(x) = x3 + 3.5x2 – 40
where x is the hydronium ion concentration. Find the hydronium ion concentration for a saturated solution (acidity equals zero) using two different methods in MATLAB (for example graphically and the roots function)